This disclosure relates to a toner amount detection sensor and an image forming apparatus.
In an image forming apparatus typified by a multifunctional peripheral and the like, an image of a document is read by an image reading unit, and then a photoconductor provided in an image forming unit is irradiated with light based on the read image to form an electrostatic latent image on the photoconductor. Thereafter, a developing agent, such as a charged toner, is supplied onto the formed electrostatic latent image to form a visible image, the visible image is transferred and fixed to a fed sheet, and then the sheet is discharged to the outside of the apparatus.
Herein, in a certain image forming apparatus capable of forming a full color image, yellow, magenta, cyan, and black colors are overlapped to form a full color image. In this case, a toner of each color is once transferred to a transfer belt as an intermediate transfer body, and then a full color image is transferred to a sheet. In the formation of the full color image, it is necessary to perform correction at predetermined timing in order to maintain color development properties and color reproducibility. In the correction, the toner amount on the transfer body is detected, and then adjustment of a development bias value, adjustment of the exposure amount, adjustment of exposure timing, and the like are performed so that a proper toner amount is set.
Herein, a technique on a sensor detecting the toner amount is known from the past.
According to a former typical optical sensor, the glossiness is measured by irradiating the surface of an object with measuring light having a predetermined angle of incidence with a projector, and then measuring a reflected light from the object surface with a light receiving unit at the reflection angle which is the same angle as the angle of incidence. Such an optical sensor has a feature in that the projector emits a single wavelength and a polarization device is provided, so that the object surface is irradiated with light having polarization in a single direction, a reflected light from the object surface is caused to transmit through a polarization beam splitter to be thereby divided into a reflected light component having polarization in the same direction as that of the measuring light and a reflected light component having a direction different therefrom, each reflected light component is measured by light receiving means provided to each reflected light component, and then the outputs from the two light receiving means are calculated to measure the glossiness.
A former typical image forming apparatus has a recording medium conveying belt which is rotatably stretched by a plurality of roller members. In such an image forming apparatus, at least one or more specular reflection light detection type optical sensors and at least one or more specular reflection light/scattering light simultaneous detection type optical sensors are disposed facing an intermediate transfer body and at least one or more specular reflection light detection type optical sensors are disposed facing the recording medium conveying belt or a second image carrying body. Such an image forming apparatus performs black toner adhesion amount control using the at least one or more specular reflection light detection type optical sensors disposed facing the recording medium conveying belt or the second image carrying body and the adhesion amount control of toners other than the black toner is performed using the at least one or more specular reflection light/scattering light simultaneous detection type optical sensors disposed facing the intermediate transfer body. Furthermore, such an image forming apparatus has a feature of performing each color alignment using the at least one or more specular reflection light/scattering light simultaneous detection type optical sensors disposed facing the intermediate transfer body and the at least one or more specular reflection light detection type optical sensors.